Chargaff's bases

Discussion of all aspects of biological molecules, biochemical processes and laboratory procedures in the field.

Moderators: Leonid, amiradm, BioTeam

CurlyQe
Garter
Garter
Posts: 12
Joined: Fri Jul 21, 2006 12:53 am

Chargaff's bases

Post by CurlyQe » Fri Jul 21, 2006 1:01 am

Chargaff said that A=T and C=G, approximately. But the numbers for A do not exactly match for T and the same for C and G. Are these mutations? Or are Chargaff's numbers not ver accurate?

SU_reptile
Coral
Coral
Posts: 145
Joined: Mon May 01, 2006 6:38 pm
Location: Katowice - Poland

Post by SU_reptile » Fri Jul 21, 2006 9:10 am

As far as I remember from high school there are derivatives of bases that may be complementary to the original ones. What's more, in tRNA first or third base (I don't remember exactly) in anticodon have some toleration for other bases.
Besides, what do you mean, by
the numbers for A do not exactly match for T and the same for C and G
. What numbers? Where did you get those information from? It may be true but what is a source of your uncertainty?

User avatar
arul
Garter
Garter
Posts: 4
Joined: Fri Jul 21, 2006 8:47 am
Location: India

Post by arul » Fri Jul 21, 2006 9:20 am

Hi mates,

Chargaff's rules state that DNA from any cell of all organisms have a 1:1 ratio of pyrimidine and purine bases and more specifically that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine. This pattern is found in both strands of the DNA.
Regards
Arul.....

CurlyQe
Garter
Garter
Posts: 12
Joined: Fri Jul 21, 2006 12:53 am

Post by CurlyQe » Fri Jul 21, 2006 1:10 pm

But if I remember correctly, that 1:1 ratio is not completely 1:1 there is a fractional difference between the bases that chargaff says have a 1:1 ratio... ack! If only I can find those numbers again!

User avatar
victor
King Cobra
King Cobra
Posts: 2668
Joined: Sat Apr 30, 2005 12:01 pm
Location: Yogyakarta, Indonesia..
Contact:

Post by victor » Fri Jul 21, 2006 1:30 pm

how about this:
Just imagine there's a deletion in one of the DNA bases. so, now the remaining bases will be mispaired won't they??
Ex: Before deletion
---ATTGCC---
---TAACGG---

After deletion
---ATGCCA---
---TAACGG---

Now, you can see that because of this kind of mutation (deletion, insertion, duplication, etc.), there'll be no exact number if A=T and C=G :lol:
Q: Why are chemists great for solving problems?
A: They have all the solutions.

CurlyQe
Garter
Garter
Posts: 12
Joined: Fri Jul 21, 2006 12:53 am

Post by CurlyQe » Fri Jul 21, 2006 7:51 pm

Aha. So they ARE mutations. Thanks!

sdekivit
King Cobra
King Cobra
Posts: 586
Joined: Sat Jul 30, 2005 7:16 pm
Location: holland
Contact:

Post by sdekivit » Fri Jul 21, 2006 8:00 pm

the rule is pure theoretical and represents the most ideal case with no mutations in the DNA as explained before. It is just a rule for how correct DNA is arranged.

kiekyon
Coral
Coral
Posts: 410
Joined: Thu Feb 16, 2006 6:10 am
Location: Malaysia

Post by kiekyon » Sat Jul 22, 2006 6:27 am

human DNA is dynamic and its molecular formula is constantly changing, as DNA is cut, nicked, extended, digested, methylated etc

CurlyQe
Garter
Garter
Posts: 12
Joined: Fri Jul 21, 2006 12:53 am

Post by CurlyQe » Sat Jul 22, 2006 4:48 pm

what is methylated?
"What can be asserted without evidence can also be dismissed without evidence." --Christopher Hitchens

rvidal
Garter
Garter
Posts: 18
Joined: Thu Jul 20, 2006 9:34 pm
Location: Portugal

Post by rvidal » Sat Jul 22, 2006 5:15 pm

CurlyQe wrote:what is methylated?

http://en.wikipedia.org/wiki/Dna_methylation
Hope this answers your question :)

User avatar
fluktuacia
Death Adder
Death Adder
Posts: 75
Joined: Thu Jul 06, 2006 4:57 pm

Post by fluktuacia » Sat Jul 22, 2006 5:29 pm


Moonake

Post by Moonake » Wed Jul 26, 2006 3:03 pm

yes, i think so... :)

Post Reply

Who is online

Users browsing this forum: No registered users and 2 guests